An organic electroluminescent device (OLED) is a flat panel displaying device which emits light by recombination of carriers injected into an organic functional layer from an anode and a cathode. The OLED has properties such as all solid state, self emitting, high contrast, ultra thin thickness, and it is capable of realizing flexible display.
Currently, electronic devices are subjected to processes of testing and aging so as to examine the device performance before they are put into the market. As for different chip bonding technology, different problems occur during the stage of testing and aging. A screen and a chip are bonded by adopting a Chip on glass (COG) manner, as shown in FIGS. 1-1 and 1-2, and the OLED comprises a substrate 103 and a lighting region 102, wherein the lighting region 102 is composed of an anode 1002, an organic functional layer 1003, and a cathode 1004 which are disposed on the substrate 103. A wiring region 101 is provided at the right and left sides and the bottom edge of the lighting region 102, and a bonding region 104 is provided at the bottom edge of the wiring region 101. Odd-number row wirings 101[1] are led from the left side of the lighting region 102, even-number row wirings 101[2] are led from the right side of the lighting region 102; and right column wirings 101[3] and left column wirings 101[4] are led from below the lighting region 102. After the row wirings and the column wirings are led out, they are concentrated at the bonding region 104 with being insulated from each other, and they are bonded at one side (edge) of the substrate, i.e., single edge boding.
For purpose of clear illustration, not all the row and column wirings are shown. Because the gap between the wirings on the COG product screen is too small, narrower conductive glue strip should be used for the too narrower space, so that (1) the conductive glue strip is likely offset so as to lead to short circuit of the screen; (2) the service life of the conductive glue strip is reduced; and (3) the wirings are broken when the conductive glue strip are press bonded with the wirings. When the gap is smaller than the minimum alignment accuracy which can be achieved in the testing and aging processes, the screen can not be lit in a short bar manner and the testing and aging can not be performed on the screen. The defective product can only be found after it is bonded with a driving chip. Currently, the screen testing and aging process can not be performed on this sort of products so that it is difficult to ensure a high yield.
The wirings of the OLED is fabricated by using a photolithography process, the important process conditions comprise etching temperature, speed, duration, etching agent concentration and the like. Over-etching will likely occur if any of the parameters is not well controlled. If there is no wiring extending region, the ends of the wirings are bonded with the driving chip. The over-etched wirings are shorter than a desired length needed for bonding, and these over-etched wirings can not be contacted with the respective chip pins or badly contacted with them, so that the corresponding rows or columns in the lighting region can not be lit. As shown in FIG. 2-1, a left column wiring 201 and a right column wiring 202 are over-etched to a length shorter than the desired length needed for bonding so that they can not be contacted with the chip pins. If the bonding position is shift upward, as shown in FIG. 2-2, so that the left column wiring 201 and the right column wiring 202 can be bonded normally. However, in this case, the chip pins will reach the bending positions of the left column wiring 203 and the right column wiring 204, and the left column wiring 203 and the right column wiring 204 can not be connected with the corresponding chip pins correctly.